How do you display a specific row when using GROUP BY?

[Vigilante]

I am getting some entries from an activity log and since many would
refer to the same client (same IP address), I added a GROUP BY clause
so there won't be multiple entries. The problem is that is only
shows the results from the first record by that IP in the log, when
I want it to show the last (ie, newest) one.

Here is my query

SELECT ip, tmstamp AS timestamp, url FROM action_log WHERE userid=0 AND tmstamp>$time GROUP BY ip ORDER BY tmstamp DESC

[_RL_Ian]

use the MAX() function:

SELECT ip, MAX(tmstamp) AS timestamp, url FROM action_log WHERE userid=0 AND tmstamp>$time GROUP BY ip ORDER BY tmstamp DESC

[Vigilante]

thanks